import java.util.HashMap;
import java.util.Scanner;

class MyTest{

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
/*        while(in.hasNext()){
            int i = in.nextInt();
        }*/
//        long ret = new Meituan().solution1(3L);
//        System.out.println(ret);
    }

    static class Meituan{
        public long solution1(long a){
            return fibonacci(a);
        }
        /*        public int fbs(int v, List<Integer> vs){
                    if(vs.size()==v)
                        return v;
                    if ((number == 0) || (number == 1)) {
                        vs.add(number);
                        return number;
                    }else {
                        int sum = fibonacci(number - 1) + fibonacci(number - 2);
                        vs.add(sum);
                    }
                }*/
        public long fibonacci(long number) {
            if ((number == 0) || (number == 1)) {
                return number;
            } else {
                return fibonacci(number - 1) + fibonacci(number - 2);
            }
        }
    }
}